I just purchased a 3.54 locker (not lsd) for my 98 323is, with this new diff. do you think i should use some sort of diff reinforcement? any recommended names?

I would check on ebay and get some cheap aluminum mounts while you have it out.

Something like this?http://www.rfdm.com/albums/album01/rf_sig1.jpg

i guess? im not looking for anything crazy. I just figured it would be good insurence considering the extra torque i will have.

Get some Turner Motorsports rear subframe reinforcements and you can also pickup some of there ALuminum diff bushings. Also if you want to you can grab one of Active Autowerks Differential Support Braces. That should tighten the back up a lot. Good Luck.